1. Field of the Invention
The present invention generally relates to shotshells and, more particularly, is concerned with a shotshell casing having a reduced volume basewad producing increased interior volume for housing a larger non-toxic shot load.
2. Description of the Prior Art
One conventional shotshell includes a casing composed of an elongated plastic tube, a metal primer, a cylindrical plastic basewad, and a cup-shaped metal head. The plastic basewad is inserted in a tight fitting relation in the bottom end portion of the tube. The bottom end portion of the tube with the basewad therein are placed inside of the metal head and mechanically locked to the head by a crimp formed into a peripheral rim at the base of the head. The basewad has a central pocket in which the primer is centrally positioned and frictionally fitted behind a propellant charge placed in the tube. An obturator shot cup containing a load of shot is housed in the tube in front of the propellant charge and the top end of the tube is closed off by an inward fold which extends over the shot load.
A shotshell casing of such construction generally provides sufficient interior volume for a lead shot load. However, due to the toxicity of lead to water fowl and the environment and health concerns about possible retention of lead in game intended for human comsumption, laws have been enacted in many states which substantially limit or even ban the use of traditional lead shot in hunting waterfowl and mandate the use of materials having little or no known toxicity, such as steel. Since steel is not as dense as lead, a larger volume load of steel shot is needed to just equal the weight of the previous lead shot load when use of steel is substituted for lead in shotshells. While the above-described shotshell casing has more than enough interior volume to house the desired load of lead shot, the interior volume is not sufficient when steel shot is substituted.
Consequently, a need exists for a practical approach to increasing the interior volume of the shotshell casing without requiring any significant change in the production equipment used for manufacturing the shotshell casing.